Abstract

AIMS:

This meta-analysis aims to compare the diagnostic performance of acoustic radiation force impulse (ARFI) elastography and transient elastography (TE) in the assessment of liver fibrosis using liver biopsy (LB) as 'gold-standard'.

METHODS:

PubMed, Medline, Lilacs, Scopus, Ovid, EMBASE, Cochrane and Medscape databases were searched for all studies published until 31 May 2012 that evaluated the liver stiffness by means of ARFI, TE and LB. Information abstracted from each study according to a fixed protocol included study design and methodological characteristics, patient characteristics, interventions, outcomes and missing outcome data.

RESULTS:

Thirteen studies (11 full-length articles and 2 abstracts) including 1163 patients with chronic hepatopathies were included in the analysis. Inability to obtain reliable measurements was more than thrice as high for TE as that of ARFI (6.6% vs. 2.1%, P< 0.001). For detection of significant fibrosis, (F ≥ 2) the summary sensitivity (Se) was 0.74 (95% CI: 0.66-0.80) and specificity (Sp) was 0.83 (95% CI: 0.75-0.89) for ARFI, while for TE the Se was 0.78 (95% CI: 0.72-0.83) and Sp was 0.84 (95% CI: 0.75-0.90). For the diagnosis of cirrhosis, the summary Se was 0.87 (95% CI: 0.79-0.92) and Sp was 0.87 (95% CI: 0.81-0.91) for ARFI elastography, and, respectively, 0.89 (95% CI: 0.80-0.94) and 0.87 (95% CI: 0.82-0.91) for TE. The diagnostic odds ratio of ARFI and TE did not differ significantly in the detection of significant fibrosis [mean difference in rDOR = 0.27 (95% CI: 0.69-0.14)] and cirrhosis [mean difference in rDOR = 0.12 (95% CI: 0.29-0.52)].

CONCLUSION:

Acoustic radiation force impulse elastography seems to be a good method for assessing liver fibrosis, and shows higher rate of reliable measurements and similar predictive value to TE for significant fibrosis and cirrhosis.

Our
prospective study included 383 consecutive subjects, with or without
hepatopathies, in which LS was evaluated by means of TE and 2D-SWE. To
discriminate between various stages of fibrosis by TE we used the following LS
cut-offs (kPa): F1-6, F2-7.2, F3-9.6 and F4-14.5.

Results

The
rate of reliable LS measurements was similar for TE and 2D-SWE: 73.9% vs.
79.9%, p=0.06. Older age and higher BMI were associated for both TE and
2D-SWE with the impossibility to obtain reliable LS measurements. Reliable LS
measurements by both elastographic methods were obtained in 65.2% of patients.
A significant correlation was found between TE and 2D-SWE measurements (r=0.68). The best LS
cut-off values assessed by 2D-SWE for predicting different stages of liver
fibrosis were: F≥1: >7.1kPa (AUROC=0.825); F≥2: >7.8kPa (AUROC=0.859); F≥3: >8kPa (AUROC=0.897) and for F=4: >11.5kPa (AUROC=0.914).

Conclusions

2D-SWE
is a reliable method for the non-invasive evaluation of liver fibrosis,
considering TE as the reference method. The accuracy of 2D-SWE measurements
increased with the severity of liver fibrosis.